SOLIDO SMART Sewage treatment plant - discharging dirty water

[ollie]

Reaching out as my solido smart is driving me insane.

2 adults 2 kids - it keeps discharging an initial burst of dirty water for a minute or so before it gradually clears up to clear discharge.

we've had Solido out to check it , they've changed the solenoid and the airlift - they can't figure out why it's doing it.

 

any experts please help!



 

[dpmiller]

Is the settling period long enough? If the airlift is known good then it can only be taking liquor at the correct height/ depth. I'd say either it isn't settling for long enough or something is stopping it from settling. This could be biological perhaps

[Crunchynut]

I don’t know this plant so my advice may not be right. For normal activated sludge I would say this : 

 

The symptoms may be because the settled sludge level in the tank is slightly above the draw level, meaning sludgey water flows until the level drops and the clear effluent is reached. Poor settlement could be due either to too much solids meaning it’s time for a desludge, or ‘bulking’ generally caused by under-aeration.

 

To see which you’ve got, do this :- (I’m assuming access is possible on your tank. I apologise if that’s not the case) :-

 

Take a large see-through container - a big sweet jar or coffee jar for example.

 

Fill it with mixed effluent eg from the aerated zone. The effluent will start to settle - note how much it has settled after 30 mins. A healthy system will settle down to 50% or less. If it has only settled to 90% or so then next do this.

 

Take a new jar full, with half taken as before and half taken from the clear effluent layer. Give the 2 halves  a gentle mix then start the timer again. Now, if after 30 minutes the %settled is roughly half what was achieved in round one, then the problem is too much solids in the tank and a desludge is needed*. If the %settled is roughly the same as round one then the problem is bulking, in which case increase the amount of aeration and give it 3 or 4 weeks to see if it improves.

 

*increased aeration might also help reduce the %solids if the sludge isn’t too old, so you might do this first and see if it helps.

 

 

Edited July 24, 2023 by Crunchynut